A drug used to treat high blood pressure could help people with diabetes to live longer, say doctors.
Two out of three diabetics die from heart disease or stroke
The drug called losartan has already been shown to significantly cut the risks of having a stroke.
But now a study in The Lancet has found it can cut the risks of diabetics dying from a heart attack by half.
The researchers said it is more effective than beta blockers, which are currently used to treat people at risk of heart disease and stroke.
Two out of three people with diabetes die from heart disease and stroke.
A study by researchers at Umea University in Sweden involving 9,000 people, published last year, found losartan was more effective at preventing strokes than beta blockers.
Beta blockers are known to reduce the risk of stroke by 40% and of a heart attack by 20%.
But losartan was found to reduce the risk of stroke by a further 25%. It also cut deaths from combined heart attack and stroke by a further 13%.
Over the past year, researchers have re-examined their data.
They selected 1,195 people who had been involved in the original study. They identified 44 people with diabetes who had since died following a heart attack.
They found that most of those who died had been taking a beta blocker. Death rates in the group taking losartan were 50% lower.
The findings suggest that while this drug could benefit all patients, it may be particularly useful in treating patients with diabetes.
"The reduction in sudden cardiac death with losartan was only evident for diabetic patients," said Professor Lars Lindholm, who carried out the study.
He said further research is needed to back up the findings.
"These results are, however, exploratory and require confirmation," he said.
That view was shared by Dr Wilbert Aronow of the New York Medical College.
Writing in an accompanying editorial in The Lancet, he said: "A large double-blind randomised trial is necessary."
Losartan is already available on the NHS. However, at the moment it is generally only prescribed to older patients. It is also three times more expensive than a beta blocker.
Professor Sir Charles George, medical director of the British Heart Foundation, welcomed the findings.
"These results are interesting and potentially important however, they require confirmation in a larger study before patients are advised to switch from atenolol to losartan."